Tuesday 5 April 2022

Auto Transcribing International HF radio stations

 For a while I have been enjoying using and learning about Software Defined Radio. I think covid lockdown in 2020 allowed society to take part in hobbies and learning much more easily than at anytime I can recall, and for me I found interest in listening to new frequencies.

I got myself a simple HF setup.

This was my first SDR i purchased. I had no idea about stuff and just bought because it looked funky.

I plugged it in and learned all the things - Zadig drivers, SDR Sharp, GQRX, Tuning, Bandwidth, Modulation and so on. My knowledge grew and grew.

Eventually I learned that it can be set to use 0-30MHz or HF radio frequencies too. in GQRX you had to set the device string like in this image

I also got myself a better antenna than the mini whip that came with the SDR package. I went with cheap advice and went with something called a long-wire antenna.

It is just a 22m length of wire and a 9:1 balun. I think a balun can be bought now for a couple of bucks, and wire can be gotten for pennies. In the picture are a green and red coil of strong string to help you throw the wire over a high tree branch and secure it outdoors, but I never really bothered with that as I wound the wire indoors around my attic space.

All in all this gave me better reception that I had with the mini whip antenna, and I could get some international stations; some Russian, some Chinese, some Spanish, Italian, German, Indian. But I had no idea what they were saying. I wondered sometimes how I could solve that problem and on night I came up with an idea.

I learned that I could take the audio headphone out from one device - A laptop or Smartphone. And connect that to the mic input on a smartphone. Then I could just use google translate or microsoft translate apps to transcribe the spoken adio into understandable text. All processed in live real-time.

I tried it on a chinese station; they talked about increased national production over last year, progress, and always progress. Then I tried on a Russian station and they spoke about russian writers. Italian radio spoke about Taylor Hawkins and the Foo Fighters. Indian music translated as lost love, infidelity and punishment.

So there. I had a better understanding of all these stations broadcasting thoughts and feelings coming from their own countries. I no longer had to imagine ehat they were saying, no more worries about the 39 Steps, Invasion, Boy scouts Brigades or other paranoid shine.

My tests are still ongoing, and I have also learned how to use live translate in a web browser. I get similar results to phone app translate, except I don't seem to get always on, i only get a few seconds translation before I have to press the button again. But it is an option. I use my iMac with software called soundflower to pipe the audio into the browser.

Thanks for reading.

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